B2425 on 2007-2011 GMC Yukon Denali XL: Heated Seat Failure Causes and Fixes

What's Unique About the 2007-2011 Gmc YUKON DENALI XL

The GMT900 platform, which includes the 2007-2014 Yukon, Tahoe, Escalade, and GM trucks, is well-known for heated seat failures. The primary issues are often not the control module itself, but the physical components. The heating element grid inside the seat cushion contains fine wires that can break from the repeated flexing of someone getting in and out of the vehicle. More significantly, the main power connector for the Heated Seat Module (located under the front *passenger* seat) was designed with single power and ground pins that are insufficient for the current draw. This causes the pins to overheat and melt the plastic connector, a very common and well-documented failure point that triggers high-resistance codes like B2425.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Driver's side heated seat does not work.
• Heated seat indicator lights turn on for a few seconds, then turn off.
• When activating the driver's heated seat, both driver and passenger heated seats are disabled.
• Heated seat indicator lights remain on, but the seat does not get warm. [⭐ MANUFACTURER TSB — highest authority] Bulletin #PIT5215A
• A clicking sound may be heard from under the seat when the function is activated and then deactivates.
• A faint burning plastic smell may be present inside the cabin, especially near the passenger footwell.

Most Likely Causes

1. Melted Heated Seat Module Connector 🔴 High Probability This is a widespread design flaw on GMT900 vehicles. The heated seat module, located under the front passenger seat, has a main connector where the single power (heavy gauge red/white or pink/white wire) and ground (heavy gauge black wire) pins are undersized for the electrical load. Over time, this high resistance generates heat, melting the plastic connector housing and causing a poor or open connection.
   How to confirm: Move the front passenger seat fully forward and upward. Unbolt the silver heated seat module (typically two 10mm nuts). Disconnect the large 12-pin connector (often labeled X305) and inspect it and the module's pins for any signs of burnt pins, melted/charred plastic, or discoloration. 🎬 See this quick walkthrough on inspecting and cleaning the module pins.
   Typical fix: Replace the connector pigtail. A widely documented permanent fix involves wiring in a new connector (Ford/Motorcraft part WPT-928 is a common cross-reference) and splitting the power and ground loads. This is done by adding jumper wires from the main power and ground wires to the adjacent, unused pins on the new connector that correspond to the extra power/ground inputs on the module, distributing the current across two pins each. 🎬 Watch: How to perform this permanent connector repair and bypass.
   Est. part cost: $20-$50
2. Failed Driver's Seat Bottom Heater Element 🔴 High Probability The heating element is made of fine grid wires embedded in the seat cushion foam. Over time, the repeated compression and flexing from entering and exiting the vehicle can cause these wires to break, creating an open circuit.
   How to confirm: Disconnect the heater element connector under the driver's seat and measure the resistance of the element with a multimeter. A reading of 'OL' (Open Loop) or infinite resistance indicates a broken element. The expected resistance is typically between 2.5 and 8.5 Ohms for the cushion. Some service documents suggest a range of 1.4-2.5 Ω, and note that the reading must be taken with the seat occupied and unoccupied to check for intermittent breaks.
   Typical fix: Replace the seat bottom heater element pad. This requires removing the seat from the vehicle and partially removing the leather seat cover (by cutting or removing hog rings) to access and replace the pad. Some owners have successfully repaired the broken grid wire with solder and tape without removing the seat.
   Est. part cost: $70-$150
3. Damaged or Chafed Wiring Under Seat 🟡 Medium Probability The wiring harness under the driver's seat is subject to movement, especially if the seat is frequently adjusted. Wires can get caught on seat tracks, stretched, or chafe against the seat frame, leading to breaks or shorts.
   How to confirm: Perform a thorough visual inspection of all wiring and connectors under the driver's seat. Look for any pinched, frayed, or broken wires. Gently tug on wires near connectors to check for breaks inside the insulation.
   Typical fix: Repair the damaged section of wire using a solder and heat-shrink butt connector. Ensure the repaired wire is properly routed and secured with zip ties to prevent future damage.
   Est. part cost: $5-$20

Rare But Worth Checking

• Failed Driver's Seat BACK Heater Element: While the bottom cushion is more common, the backrest element can also fail and cause the B2425 code. One owner on a forum replaced the bottom element to no avail, only to later find the backrest element had severely burned through the foam. The backrest element often acts as the 'master' element in the circuit.
• Failed Heated Seat Control Module: This is rarely the cause of the failure. The module is robust, and the issue is almost always with the wiring, connector, or the heating element itself. Do not replace the module unless all other components have been tested and confirmed to be good.
• Reversed Element Connectors (Accessory Seats): As noted in TSB #PIT5215A, if GM Accessory Heated Seats were installed, it's possible the seat back and bottom element connectors were reversed. The harness has two identical connectors; the longer lead (covered with convoluted tubing) goes to the seat back, and the shorter lead (covered with tape) goes to the seat bottom.

Diagnosis Steps

1. Verify the symptom. Confirm that the driver's heated seat is inoperative and that the indicator lights either don't stay on or stay on without producing heat.
2. Scan for codes. Use a scanner capable of reading GM-specific Body (B) codes to confirm B2425 is present and note any symptom bytes (e.g., 0D for high resistance).
3. Inspect Heated Seat Module Connector (Under Passenger Seat). This is a top priority. Move the passenger seat up and forward. Unbolt and inspect the large connector (X305) on the heated seat module for any signs of melting or burnt pins, especially on the heavy-gauge power and ground wires.
4. Inspect Under-Seat Wiring. Visually inspect the wiring harness and connectors under the driver's seat for obvious signs of damage, such as chafing, pinching, or breaks.
5. Test Heater Element Resistance. Disconnect the driver's seat heater element connectors. Using a multimeter, measure the resistance across the two pins for the seat bottom element. A normal reading is between 2.5-8.5 ohms. Repeat for the seat back element (expected range 3.5-11.5 ohms). A reading of infinity or 'OL' confirms a broken element. Wiggle the seat cushion while testing to expose intermittent breaks.
🎬 Watch: A mechanic's guide to troubleshooting and testing seat heater circuits.
6. Check Fuses. While a blown fuse is unlikely to cause a high-resistance code, it's a quick check. The main fuse is often labeled 'MBEC 1' (50A) in the underhood block, feeding a 'SEAT CB' circuit breaker in the left instrument panel fuse block. A blown fuse could occur after a connector melts.
7. Isolate the Fault. If the elements and main connector are good, the fault lies in the wiring between the module and the element. Test for continuity on these wires.

Parts You'll Likely Need

• Front Seat Cushion Heater Element (OEM #23168136) — This is a very common failure point. The wires inside the pad break from use, causing an open circuit and triggering code B2425. Verify part number with VIN.
  Trusted brands: ACDelco, Dorman
  OEM price range: $100-$150
  Aftermarket price range: $70-$100
• Heated Seat Module Connector Pigtail (OEM #WPT-928 (Motorcraft - confirmed cross-reference), ACDelco PT2386 (88862305)) — If the connector at the heated seat module has melted due to the design flaw, this pigtail is needed to replace the damaged plastic and terminals. The Ford/Motorcraft part is widely used for this repair.
  Trusted brands: Motorcraft, ACDelco, Dorman
  OEM price range: $30-$50
  Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

• B2430 — This is the equivalent code for the passenger (right) side seat heater circuit. It's common for both seats to fail around the same time due to similar wear, or for a melted module connector to affect both circuits.
• B1935 — This is another related heated seat code that can be set for a driver's side fault, sometimes indicating a problem with the temperature sensor (thermistor) circuit within the seat or the seat back element.

Technical Service Bulletins (TSBs) & Recalls

• PIT5215A: Addresses inoperative GM Accessory Heated Seats, noting that codes like B2425 may be present. The cause is often that the seat back and bottom element connectors were reversed during installation. The longer harness lead goes to the seat back, the shorter to the cushion.

Platform-Specific Known Issues

• The provided TSB #PIT5215A specifically addresses heated seat inoperability on these vehicles, sometimes accompanied by code B2425, and points to inspecting the wiring harness and connectors, particularly for reversed element connectors on accessory kits. [⭐ MANUFACTURER TSB — highest authority] Bulletin #PIT5215A
• A widespread, well-documented issue is the melting of the main power connector at the heated seat module under the passenger seat due to an undersized single-pin design for power and ground.

Mechanic-Grade Diagnostic Values

• Driver's Seat Cushion Heater Element Resistance — expected: 2.5 - 8.5 Ohms. Some service manuals state a tighter range of 1.4 - 2.5 Ohms.. Failure: A reading of 'OL' (Open Loop) or infinite resistance indicates a broken element. A reading significantly above the range indicates high resistance.
• Driver's Seat Back Heater Element Resistance — expected: 3.5 - 11.5 Ohms.. Failure: A reading of 'OL' or significantly outside this range indicates a failure.
• Heated Seat Thermistor Signal Voltage — expected: 4.8 - 5.2 Volts (between signal circuit and ground).. Failure: Voltage outside this range points to a fault in the thermistor or its wiring.
• Heated Seat Thermistor Resistance — expected: Varies with temperature (Negative Temperature Coefficient). Common values are 10kΩ or 50kΩ at 25°C.. Failure: An open or shorted reading, or a value that doesn't change with temperature, indicates a failed thermistor.

Hidden / Shadow Codes Worth Checking

• B2425 0D: Left Seat Heater Cushion Circuit Resistance Above Threshold. This is the most common symptom, pointing directly to an open circuit from a broken element or melted connector. (see via GM-specific scan tool like a Tech 2 or GDS2.)
• B2425 0E: Left Seat Heater Cushion Circuit Resistance Below Threshold. This indicates a short circuit in the heating element or wiring. (see via GM-specific scan tool like a Tech 2 or GDS2.)
• B2425 0B: Left Seat Heater Cushion Circuit Current Above Threshold. This also points to a short circuit condition. (see via GM-specific scan tool like a Tech 2 or GDS2.)
• B2425 04: Left Seat Heater Cushion Circuit Open. This can be set if the module commands the heater on but does not detect a corresponding temperature change from the thermistor within a set time (e.g., 210 seconds). (see via GM-specific scan tool like a Tech 2 or GDS2.)

Scan Tool Commands That Help

• Tech 2 / GDS2: Heated Seat Test / Output Control — Use this bidirectional command to manually activate the driver's heated seat element. If the seat heats up when commanded by the scan tool but not the switch, it suggests an issue with the switch or the communication to the module. If it still doesn't heat, it confirms the fault is in the module, wiring, or element.
• Tech 2 / GDS2: View Captured Data / Data Display — Monitor the live data for the heated seat thermistor temperature and element command status. This allows you to see if the module is attempting to activate the heater and what temperature it is reading from the seat.

Wiring & Ground Locations

• Heated/Cooled Seat Control Module — Under the front PASSENGER seat, typically secured by two 10mm nuts. This single module controls both front seats.. This is the brain of the system and, more importantly, where the main power connector (X305) is located, which is the most common failure point due to melting.
• Connector X305 — The large 12-pin main connector that plugs into the Heated/Cooled Seat Control Module under the passenger seat.. The power and ground pins on this connector are known to overheat and melt, causing high resistance and triggering B2425 0D.
• G303 — At the base of the driver's side 'B' pillar, near the floor.. This is a primary chassis ground point for the driver's seat modules and accessories. A corroded or loose G303 can cause various difficult-to-diagnose electrical issues, though it's less common than the melted connector.
• MBEC 1 Fuse — In the Underhood Fuse Block on the driver's side of the engine compartment. It is typically a 50-Amp square J-Case fuse.. This is the main fuse that supplies power to the instrument panel fuse block for the seat circuits. A failure here would kill power to both seats.

Real Owner Repair Stories

• Tahoe Yukon Forum & multiple YouTube videos (2011 Chevy Suburban / GMC Yukon) — Driver's heated/cooled seat stopped working. Lights on the door switch would illuminate but then turn off. A burning plastic smell was noticed. Eventually, the main fuse for the circuit blew.
  ❌ Tried (didn't work) Initially replacing the fuse, which would blow again., Cleaning the melted plastic off the original connector terminals provided only a temporary fix before the problem returned.
  ✅ What actually fixed it The melted 12-pin connector (X305) at the heated seat module under the passenger seat was replaced with a new pigtail (Motorcraft WPT-928). The crucial step was modifying the wiring: the single heavy-gauge power wire was spliced to feed BOTH power input pins on the new connector, and the single heavy-gauge ground wire was spliced to feed BOTH ground pins. This distributes the high current load across two sets of terminals, preventing the overheating and melting from recurring.

OEM Part Supersession History

• 15232559, 20792748 → 23168136 — Part number consolidation and potential minor updates to the element design over the production run.
  Heads up: Part 23168136 is listed for 2014-2018 models but is commonly used and fits 2007-2013 models as a replacement, though VIN verification is always recommended.
• GM 15326110 → ACDelco PT2386 (88862305) — Standard part number update from GM to ACDelco branding.
  Heads up: This is the official GM/ACDelco pigtail. However, many technicians and DIYers prefer the Ford/Motorcraft WPT-928 pigtail as it is identical in form and often considered more robust or readily available.

Model Year Variations Within This Range

• 2007-2010: Models with cooled seats used a Thermo-Electric Device (TED) that could provide both heating and cooling, a more complex system.
• 2011-2014: GM switched to a simpler "ventilated seat" system that used a fan to blow ambient cabin air through the perforated seats, while retaining a separate resistive heating element pad for the heat function. This simplified the system but the common B2425 failure points (element, connector) remained the same.